Stencil printing machine

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stencil printing machine perforating stencil sheet mounted to a printing drum and capable of carrying out printing operation by using thereof, particularly to a stencil printing machine supplying perforated stencil sheet to a plurality of printing drums.

2. Description of the Related Art

FIG. 4

is a side view showing a conventional stencil printing machine. Stencil sheet S to be perforated is wound in a roll-like shape and is rotatably supported. The stencil sheet S reeled out from the stencil sheet S in the roll-like shape is constituted by a shape of a continuous strip. The reeled-out stencil sheet S is pinched between a thermal head

50

and a platen roller

51

.

The stencil sheet S is heated and perforated by the thermal head

50

(stencil making operation). In carrying out the heating and stencil making operation, the stencil sheet S is transferred by rotation of the platen roller

51

while being brought into contact with the thermal head

50

. Thereafter, the stencil sheet S is contained in a storage box

52

until finishing the heating and stencil making operation of one block by the thermal head

50

. The stencil sheet S is contained in the storage boxes

52

by feeding the stencil sheet only by the platen roller

51

while upper and lower load rollers

53

and

54

disposed above the storage box

52

are stationary and pinching the stencil sheet S. Further, a common transfer path

55

is arranged at the front side of the storage box

52

. The common transfer path

55

is provided with cutter means

56

for cutting one block of the perforated stencil sheet S.

After finishing the heating and stencil making operation, the thermal head

50

is moved in an upper direction to thereby release the stencil sheet S from being pinched by the thermal head

50

along with the platen roller

51

. The stencil sheet S finished with the heating and stencil making operation is

In the meantime, according to the stencil printing machine shown by

FIG. 4

, the perforated stencil sheet S is transferred to two of the printing drums

57

. Therefore, the stencil printing machine is provided with respective transfer paths

58

for feeding the stencil sheet S from the common transfer path

55

to the respective printing drums

57

and a switch mechanism

60

for selectively switching the paths to communicate the paths from the common transfer paths

55

to either of the transfer paths

58

. Each of the transfer paths

58

guides the stencil sheet S between upper and lower guide plates

58

a

and

58

b

and transfers the stencil sheet S by a plurality of transfer roller pairs

59

. The switch mechanism

60

is arranged between the common transfer path

55

and the respective transfer paths

58

and is provided with a shunt transfer path

62

movable by a solenoid

61

. The shunt transfer path

62

moved by the solenoid

61

opens the path to communicate from the common transfer path

55

to one of the transfer paths

58

or opens the path to communicate from the common transfer path

55

to the other of the transfer paths

58

.

The stencil sheet S transferred to one of the transfer paths

58

or the other of the transfer paths

58

, is pinched by a clamp plate

63

disposed at the printing drum

57

at its front end, fixed to the printing drum

57

, thereafter transferred by rotation of the printing drum

57

and is made to wrap on a peripheral face of the printing drum

57

. Further, the stencil sheet S is cut into one block by the cutter means

56

during the transfer operation or in arrival at the printing drum

57

.

Further, the stencil printing machine shown by

FIG. 4

is adopted in a printing machine. A portion of a constitution of the printing machine is not illustrated. A portion of a peripheral wall

64

of the printing drum

57

is ink-permeable. There is provided ink supply means, not illustrated, for supplying ink to an inner face of the peripheral wall

64

at inside of the printing drum

57

. There is provided pressing means, not illustrated, for pressing print sheet to the printing drum

57

below the printing drum

57

. The printing machine rotates the printing drum

57

, feeds print sheet between the printing drum

57

and the pressing means at predetermined timings and presses print sheet at image portions of the stencil sheet S mounted to the printing drum

57

. Printing ink supplied from inside of the printing drum

57

passes through the peripheral wall

64

of the printing drum

57

and is transcribed from perforated portions of the stencil sheet S onto print sheet to thereby form picture.

However, according to the above-described conventional stencil printing machine, when the perforated stencil sheet S is transferred to the printing drum

57

, there is needed the long transfer path

58

for transferring the perforated stencil sheet S to the printing drum

57

particularly remote from a position where the stencil printing machine per se is installed. Further, when the transfer path

58

is long, a large number of the transfer roller pairs

59

is needed. Further, there is needed the switch mechanism

60

for switching the paths from the common transfer path

55

to the respective transfer paths

58

. As described above, there poses a problem that in the conventional stencil printing machine, a number of constituent parts for transferring the perforated stencil sheet S is large.

Further, when a large number of the transfer roller pairs

59

is used, there is a concern in which balance of pinch pressure at the respective transfer roller pairs

59

is delicately deteriorated and the stencil sheet S is transferred in an oblique direction. Thereby, there poses a problem that there causes mounting position failure in which a position of mounting the stencil sheet S to the printing drum

57

is not disposed at a predetermined position or wrinkle is caused in the stencil sheet S mounted to the printing drum

57

.

Further, by prolonging the transfer path

58

, there poses a problem that the stencil sheet S is clogged between the upper and the lower guide plates

58

a

and

58

b

or a front end of the stencil sheet is folded. The above-described problem is liable to occur particularly in the stencil sheet S used in the printing machine since the stencil sheet S comprises a sheet produced by pasting a heat-sensitive film together with a porous supporter such as Japanese paper and accordingly, the stencil sheet S is easy to fold.

Hence, in order to resolve the above-described problems, it is an object of the present invention to provide a stencil printing machine capable of feeding stencil sheet to a plurality of printing drums without causing mounting failure or transfer failure.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a stencil printing machine comprising a plurality of printing drums arranged to be spaced apart from each other at intervals and wound with perforated stencil sheet at respective peripheral walls thereof, a stencil making unit for perforating the stencil sheet, and a moving mechanism for supporting the stencil making unit to be movable relative to the respective printing drums.

According to a second aspect of the present invention, there is provided the stencil printing machine according to the first aspect wherein the moving mechanism comprises a guide portion for supporting the stencil making unit movably relative to the respective printing drums, a drive portion for moving the stencil making unit via the guide portion, and position detecting means for detecting that the stencil making unit is disposed at a desired position.

According to a third aspect of the present invention, there is provided a stencil printing machine comprising a plurality of printing drums arranged horizontally to be contiguous to each other at intervals such that respective axis lines thereof are made parallel to each other and respective peripheral walls being wound with perforated stencil sheets, a stencil making unit for perforating and delivering the stencil sheets to be wound around the printing drums, a guide portion provided along a moving path including a plurality of mounting positions at which the stencil making unit respectively supplies the stencil sheets to the respective printing drums and supporting the stencil making unit to be capable of moving along the moving path, a drive portion provided at the stencil making unit for moving the stencil making unit along the guide portion, and position detecting means arranged along the moving path of the stencil making unit and having a number larger than a number of the printing drums provided along the moving path such that the stencil making unit can be detected to be disposed at the mounting positions and disposed at a middle position between contiguous two of the mounting positions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a side view showing an example of a stencil printing machine according to the present invention;

FIG. 2

is a side view showing operation of the stencil printing machine;

FIG. 3

is a side view showing the operation of the stencil printing machine; and

FIG. 4

is a side view showing a conventional stencil printing machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A specific explanation will be given for embodiments of the present invention in reference to the drawings as follows.

FIG. 1

is a side view showing an example of a stencil printing machine according to the present invention and FIG.

2

and

FIG. 3

are side views showing an operation of the stencil printing machine.

The stencil printing machine according to the example is provided with a perforating function for heat-sensitively perforating a stencil sheet by a thermal head and is adopted in a printing machine for carrying out perforation printing on a print sheet by using a perforated stencil sheet.

As shown by

FIG. 1

, there is provided printing drums

2

at inside of a machine body

1

of the printing machine. The printing drum

2

is provided with a peripheral wall

3

substantially in a cylindrical shape at least a portion of which is ink-permeable, a clamp plate

4

provided at an outer peripheral face of the peripheral wall

3

and ink supply means, not illustrated, provided on an inner side of the peripheral wall

3

for supplying ink to an inner peripheral face of the peripheral wall

3

. The clamp plate

4

is fixing means for clamping a front end portion of a stencil sheet wound on the outer peripheral face of the peripheral wall

3

. The printing drum

2

is driven to rotate on an axis line of its own. Further, there is provided pressing means

5

for pressing a print sheet to the printing drum

2

below the printing drum

2

. As the pressing means

5

, as shown by

FIG. 1

, there is provided a press roller which can be brought into contact with the printing drum

2

and can be separated therefrom. Other than these, although not illustrated, the pressing means

5

is provided with a press drum having a diameter same as that of the printing drum

2

and rotated in contact with the printing drum

2

in a state of being wound with the print sheet.

According to the printing machine, there is provided a plurality of the printing drums

2

. According to the embodiment, there are provided two printing drums

2

. The respective printing drums

2

are arranged such that respective axis lines of their own are in parallel with each other and horizontal. Further, there is provided transfer means

40

between the respective printing drums

2

for transferring the print sheet printed by one of the printing drums

2

to the other of the printing drums

2

.

According to the transfer means

40

, an endless belt

42

is made to span two rollers

41

arranged at vicinities of the respective printing drums

2

. The belt

42

is circulated by driving the rollers

41

. There are provided sucking mechanisms

43

of, for example, fans between the respective rollers

41

for sucking the print sheet to be transferred and pulling the print sheet to the belt

42

.

In this way, the stencil printing machine having a plurality of the printing drums

2

enables multiple (multiple color) printing for printing on the print sheet at one of the printing drums

2

and printing on the print sheet successively at the other of the printing drum

2

.

The stencil printing machine adopted to the above-described printing machine is arranged in a frame

6

supported in the machine body

1

. The frame

6

is provided with a master holder

7

for rotatably holding a stencil sheet S wound in a roll-like shape. The stencil sheet S is a sheet produced by pasting together a heat-sensitive film and a porous supporter. Further, an upper side of the frame

6

can be opened from a closed state shown by

FIG. 1

by a press plate frame

9

opened and closed via a support shaft

8

.

Between the master holder

7

and the printing drum

2

on

15

the right side of

FIG. 1

, there are respectively provided a nip roller

10

and a tension roller

11

, a platen roller

12

and a thermal head

13

and a cutter unit

14

in this order from the side of the master holder

7

. The stencil sheet S is transferred via the rollers and the like and is heat-sensitively perforated by the thermal head

13

.

As shown by

FIG. 1

, the nip roller

10

is rotatably supported via a shaft

15

supported by the side of the press plate frame

9

. The press plate frame

9

is formed with a long hole (not illustrated) which is long in the vertical direction and the shaft

15

is supported via the long hole. Thereby, the nip roller

10

is movable in the up and down directions along the long hole and is brought into contact with the tension roller

11

by its own weight.

The tension roller

11

is supported rotatably via a shaft

16

supported by the side of the frame

6

below the nip roller

10

. A peripheral face of the tension roller

11

is provided with a high friction material such as rubber or is surface-treated to produce a high friction state. Therefore, the stencil sheet S transferred in contact with the tension roller

11

is restrained from being slipped. Further, a torque limiter (not illustrated) is provided at the shaft

16

of the tension roller

11

. Therefore, in transferring the stencil sheet S, the tension roller

11

is not rotated idly but constant torque is produced.

The stencil sheet S reeled out from the stencil sheet S in the roll-like shape, is transferred by being pinched between the nip roller

10

and the tension roller

11

. The tension roller

11

prevents slippage of the transferred stencil sheet S by the above-described surface treatment. Further, since the torque limiter is provided at the shaft of the tension roller

11

, the tension roller

11

is not rotated idly but constant torque is applied in transferring the stencil sheet S. Thereby, the stencil sheet S pinched by the tension roller

11

and the nip roller

10

is transferred between the platen roller

12

and the thermal head

13

in a state of being always applied with constant tension.

As shown by

FIG. 1

, the thermal head

13

is attached to the press plate frame

9

. The thermal head

13

is formed substantially in a shape of a strip plate which is long in the depth direction of

FIG. 1

, installed orthogonally to a transfer direction of the transferred stencil sheet S and is brought into contact with an upper face of the stencil sheet S. At a lower face of the thermal head

13

, there is formed a processing face having a plurality of heat generating members aligned in parallel with the width direction of the stencil sheet S for perforating the stencil sheet by heat. Further, the thermal head

13

can be moved in a direction of approaching the platen roller

12

or retracting therefrom by driving means

17

and in perforating the stencil sheet S, the processing face of the thermal head

13

is opposed to the platen roller

12

and is separated upward from the platen roller

12

after perforation.

The driving means

17

is provided on the side of the press plate frame

9

and is provided with a solenoid

18

and an arm

19

. An operating rod

20

of the solenoid

18

is attached with an end of a tension coil spring

21

. Other end of the tension coil spring

21

is attached to a portion of the arm

19

. The arm

19

is provided pivotably relative to the press plate frame

9

. Further, the arm

19

is attached with the thermal head

13

. The thermal head

13

is pushed down to a lower side via the arm

19

urged by spring force of the tension coil spring

21

in a state in which the solenoid

18

is not operated and the operating rod

20

is drawn and approaches the platen roller

12

. Further, the thermal head

13

is lifted upwardly via the tension coil spring

21

and the arm

19

in a state in which the solenoid

18

is operated and the operating rod

20

is extracted and is separated from the platen roller

12

.

The platen roller

12

is disposed to be opposed to the lower side of the thermal head

13

and provided on the side of the frame

6

and is driven to rotate in the counterclockwise direction of

FIG. 1

by a drive mechanism, not illustrated, provided on the side of the frame

6

.

Further, thermal head claws

22

are provided at both ends of the thermal head

13

. The thermal head claws

22

are engaged with a shaft

23

of the platen roller

12

when the press plate frame

9

is closed and the thermal head

13

and the platen roller

12

are positioned to be opposed to each other.

As described above, the stencil sheet S which has passed through the tension roller

11

and the nip roller

10

, is pinched between the platen roller

12

and the thermal head

13

which are brought into contact with each other. The stencil sheet S is perforated by being heated and perforated by the thermal head

13

while being transferred by the rotating platen roller

12

. The stencil sheet S after perforation is transferred by driving to rotate the platen roller

12

and is delivered to the side of the cutter unit

14

.

The cutter unit

14

is provided at the frame

6

and is constituted to pass the stencil sheet S. At the portion of passing the stencil sheet S, there is provided a cutter movable in the depth direction of

FIG. 1

, that is, in the width direction of the stencil sheet S. Further, the stencil sheet S is cut in accordance with movement of the cutter.

In this way, respective constitutions of the above-described stencil printing machine constitute a stencil making unit with the frame

6

as its base portion. Further, the frame

6

(stencil making unit) is made movable by a moving mechanism relative to the machine body

1

of the printing machine.

An explanation will be given of the moving mechanism as follows.

The frame

6

is supported on the side of the machine body

1

by a guide portion such that the frame

6

can be moved from a position shown in

FIG. 1

in the left direction to the above-described respective printing drums

2

. With regard to the guide portion, although not particularly illustrated, for example, there is conceivable a constitution in which guide rails are provided at the machine body

1

and the frame

6

is engaged with the guide rails to move therealong. Further, the guide portion according to the embodiment is constituted such that the frame

6

is moved in the horizontal direction since the respective printing drums

2

are arranged such that axis lines of their own are made horizontal. In this way, the guide portion is supported such that the frame

6

(stencil making unit) is moved in a direction in correspondence with arrangement of a plurality of the printing drums

2

.

The frame

6

movably supported by the guide portion is driven to move by a drive unit. The drive unit is arranged on the side of the machine body

1

and on the side of the frame

6

. On the side of the machine body

1

, there is provided a rack gear

25

along a direction of moving the frame

6

. Further, the frame

6

is provided with a gear

26

which is moved by itself and is always in mesh with the rack gear

25

. The gear

26

is fixed to a shaft

29

rotatably supported by the side of the frame

6

. Further, a drive motor

27

is provided at;the frame

6

. A drive gear

28

is provided at an output shaft of the drive motor

27

. The drive gear

28

is in mesh with a driven gear

30

fixed to the shaft

29

of the gear

26

.

When the drive motor

27

is driven, rotation is transmitted to the shaft

29

via the drive gear

28

and the driven gear

30

and the gear

26

is rotated. The gear

26

is rolled by its own rotation in a state of being in mesh with the rack gear

25

. Thereby, the shaft

29

is moved along the rack gear

26

and the frame

6

is moved.

The position of the frame

6

moved by the drive unit is detected by position detecting means. Position sensors

31

are provided on the side of the machine body

1

. The position sensors

31

according to the embodiment is paired with light projecting and receiving portions. The position sensors

31

are arranged at a total of three locations of positions for detecting that the frame

6

is moved to positions at which an end portion of the perforated stencil sheet S is to be delivered to the two printing drums

2

and a position for detecting that the frame

6

is moved at a position substantially a middle between the respective printing drums

2

. Further, on the side of the frame

6

, there is provided a shield plate

32

for shielding light projecting and receiving portions of the position sensors

31

. The shield plate

32

shields the light projecting and receiving portions of the respective position sensors

31

in accordance with movement of the above-described frame

6

.

Here, an explanation will be given of a specific relation between the position sensors

31

and the shield plate

32

in accordance with the movement of the frame

6

in reference to FIG.

1

through FIG.

3

.

As shown by

FIG. 1

, when the frame

6

(stencil making unit) is disposed at the position at which the stencil sheet S is to be delivered to the printing drum

2

on the right side, the shield plate

32

shields only the position sensor

31

a

on the right side. In order to set the stencil making unit at the position, the frame

6

may be moved from the state shown in

FIG. 1

in the right direction where all of the position sensors

31

are not shielded by the shield plate

32

, and then, the frame

6

is moved to return in the left direction from the position and movement of the frame

6

may be stopped at a position where the position sensor

31

a

is shielded again by the shield plate

32

.

Further, as shown by

FIG. 2

, when the frame (stencil making unit) is disposed at a position at which the stencil sheet S is to be delivered to the printing drum

2

on the left side, the shield plate

32

shields both of the position sensor

31

c

on the left side and the position sensor

31

b

at the center. In order to set the stencil making unit at the position, the frame

6

may be moved in the left direction from a state in which the shield plate

32

shields only the position sensor

31

b

and movement of the frame

6

may be stopped at a position where the position sensor

31

c

is shielded by the shield plate

32

.

Further, as shown by

FIG. 3

, when the frame

6

(stencil making unit) is disposed at a middle position between the respective printing drums

2

, the shield plate

32

shields both of the position sensor

31

b

at the center and the position sensor

31

a

on the right side. In order to set the stencil making unit at the position, when the stencil making unit is moved from the state of

FIG. 1

, the frame

6

may be moved in the left direction from a state in which the shield plate

32

shields only the position sensor

31

a

and movement of the frame

6

may be stopped at a position at which the position sensor

31

b

is shielded by the shield plate

32

. Further, when the frame

6

is moved from the state of

FIG. 2

, the frame

6

is moved in the right direction and the movement is continued in the right direction even from a state in which the position sensor

31

c

is not shielded by the shield plate

32

and the position sensor

31

a

is shielded by the shield plate

32

. Further, the frame

6

may be moved to return in the left direction from a position at which the position sensor

31

b

is not shielded by the shield plate

32

(state in which only the position sensor

31

a

is shielded by the shield plate

32

) and movement of the frame

6

may be stopped at a position at which the position sensor

31

b

is shielded again by the shield plate

32

.

Next, an explanation will be given of operation of the above-described stencil printing machine.

In order to set the stencil sheet S between the above-described respective rollers, the press plate frame

9

is opened to the upper side. At this occasion, the nip roller

10

and the thermal head

13

arranged on the side of the press plate frame

9

are lifted along with the press plate frame

9

and the nip roller

10

is separated from the tension roller

11

and the thermal head

13

is separated from the platen roller

12

. From this state, the stencil sheet S in a shape of a continuous strip is reeled out from the stencil sheet S in the roll-like shape contained in the master holder

7

. The stencil sheet S is arranged to be brought into contact with respective peripheral faces on upper sides of the tension roller

11

and the platen roller

12

. Further, the press plate frame

9

is closed and the stencil sheet S is pinched between the nip roller

10

and the tension roller

11

and between the thermal head

13

and the platen roller

12

.

In the stencil making operation, image information is provided to the thermal head

13

. The image information can be read by, for example, an original reading apparatus, not illustrated. The thermal head

13

forms a perforated image in correspondence with the image information at the stencil sheet S pinched between the thermal head

13

and the platen roller

12

. During the stencil making operation, the stencil sheet S is transferred to direct its front end to the printing drum

2

to which the frame

6

(stencil making unit) corresponds only by a drive force of the platen roller

12

.

In the above-described stencil making operation, the stencil sheet S which is reeled out from the stencil sheet S in the roll-like shape and is transferred, is pinched between the tension roller

11

having the torque limiter and the nip roller

10

and therefore, the stencil sheet S is transmitted to the side of the thermal head

13

in a state of being always exerted with constant tension. Therefore, slack is not caused in the transferred stencil sheet S and wrinkle is difficult to cause in the stencil sheet S after perforation.

Further, the stencil printing machine according to the embodiment carries out the stencil making operation and carries out operation of mounting the stencil sheet S to the printing drum

2

. Therefore, the front end of the stencil sheet S which has been perforated by the above-described stencil making operation is delivered to the clamp plate

4

of the printing drum

2

by rotation of the platen roller

12

. The front end of the stencil sheet S is fixed to the printing drum

2

by the clamp plate

5

. Further, the printing drum

2

is rotated and operation of mounting to make the stencil sheet S wrap on the peripheral face of the printing drum

2

is carried out. Further, in the operation of mounting the stencil sheet S to the printing drum

2

, at a time point at which the mounting operation of one block has been finished, a processing face

13

a

of the thermal head

13

is separated from the platen roller

12

by the driving means

17

, the stencil sheet S is relieved of being pinched and the stencil sheet S is cut by the cutter unit

14

.

The stencil printing machine is engaged with a perforating and mounting operation, described above, and the perforating and mounting operation is carried out to the other printing drum

2

by moving the frame

6

(stencil making unit).

After carrying out the perforating and mounting operation with regard to the printing drum

2

on the right side as shown by

FIG. 1

, the perforating and mounting operation is carried out with regard to the printing drum

2

on the left side. With regard to the movement of the frame

6

, the movement is carried out by the above-described moving mechanism. Further, with regard to positioning of movement position of the frame

6

, the positioning is carried out by the above-described position detecting means. That is, by driving the drive motor

27

of the moving mechanism, the frame

6

is moved to the printing drum

2

on the left side. Further, when the frame is detected to dispose at a position in correspondence with the printing drum

2

on the left side as shown by

FIG. 2

by the position sensor

31

c

of the position detecting means, movement of the frame

6

is stopped. Further, after moving the frame

6

, the above-described perforating and mounting operation is carried out. Thereby, operation of mounting the perforated stencil sheet S to the respective printing drums

2

is finished.

In the printing operation, the respective printing drums

2

are rotated and as shown by an arrow mark A of

FIG. 1

, a print sheet is delivered between one (left side of

FIG. 1

) of the printing drums

2

and a corresponding one of the pressing means

5

at a predetermined timing. The pressing means

5

presses the print sheet to an image portion of the stencil sheet S mounted to one of the printing drums

2

. Printing ink supplied from the inner peripheral wall of one of the printing drums

2

passes through the peripheral wall

3

and is transcribed from a perforated portion of the stencil sheet S onto the print sheet. The print sheet is formed with a perforated image at one of the printing drums

2

.

With regard to the print sheet formed with the perforated image at one of the printing drums

2

, the print sheet is delivered between the other (right side of

FIG. 1

) of the printing drums

2

and a corresponding one of the pressing means

5

via the transfer means

40

. The pressing means

5

presses the print sheet to an image portion of the stencil sheet S mounted to the other of the printing drums

2

. Printing ink supplied from the inner peripheral wall of the other of the printing drums

2

passes through the peripheral wall

3

and is transcribed from a perforated portion of the stencil sheet S onto the print sheet. The print sheet is formed with a perforated image at the other of printing drums

2

and the print sheet is discharged as shown by an arrow mark B of FIG.

1

.

Further, the stencil printing machine not only can be moved to positions in correspondence with one and the other of the printing drums

2

, described above, but also can move to the middle position between the respective printing drums

2

. With regard to the movement of the frame

6

(stencil making unit) to the middle position, the movement is carried out by the above-described moving mechanism. Further, with regard to positioning at the movement position of the frame

6

, the positioning is carried out by the above-described position detecting means. That is, the frame

6

is moved to the middle position between the respective printing drums

2

by driving the drive motor

27

of the moving mechanism. Further, when the frame

6

is detected to be disposed at the position in correspondence with the middle position between the respective printing drums

2

as shown by

FIG. 3

by the position sensor

31

b

of the position detecting means, the movement of the frame

6

is stopped. In this way, by positioning the frame

6

(stencil making unit) at the middle position between the respective printing drums

2

, distances of moving the frame

6

(stencil making unit) to both of the printing drums

2

can be made uniform and in selecting the respective printing drums

2

, the stencil making unit can swiftly be moved.

Therefore, according to the stencil printing machine constituted in this way, by enabling the stencil making unit perforating the stencil sheet S to move to a plurality of the printing drums

2

, the respective transfer paths and the transfer roller pairs for transferring the stencil sheet S to the respective printing drums

2

and the switch mechanism for selecting the respective transfer paths are dispensed with. Thereby, constituent parts for transferring the stencil sheet S can be reduced.

Further, since the transfer paths and transfer roller pairs are not provided, meandering of the stencil sheet S in transfer operation is not caused and therefore, positions of attaching the stencil sheet S to the respective printing drums

2

become predetermined positions and mounting position failure or wrinkle of the stencil sheet S can be eliminated.

Further, since he respective transfer paths and the transfer roller pairs are not provided, the stencil sheet S is not clogged between upper and lower guide plates constituting the transfer path and folding is not caused at the front end of the stencil sheet S.

Further, although the stencil printing machine according to the above-described embodiment shows an example of adopting the stencil printing machine to the printing machine having two of the printing drums

2

, full color printing can be carried out by providing three of the printing drums

2

and carrying out mounting and printing operation in which the three printing drums

2

are distributed with colors of cyan, magenta and yellow.

Further, although the stencil printing machine according to the above-described embodiment is constituted such that the frame

6

(stencil making unit) is moved in the horizontal direction since the plurality of printing drums

2

are arranged such that the respective axis lines are made horizontal, in the case in which in arranging a plurality of the printing drums

2

, the respective axis lines are made in parallel with each other and the printing drums

2

are arranged on a locus in, for example, a shape of a circular arc, the stencil printing machine may be constituted such that the frame

6

(stencil making unit) is moved in the circular arc shape along the locus. In this way, movement of the frame

6

(stencil making unit) is derived from an arrangement locus constituted by the plurality of printing drums

2

.

As has been explained, according to the stencil printing machine of the present invention, the transfer paths and the transfer roller pairs for transferring the stencil sheet to the respective printing drums and the switch mechanism for selecting the respective transfer paths are dispensed with by moving the stencil making unit perforating the stencil sheet to the plurality of printing drums.

Thereby, constituent parts for transferring the stencil sheet can be reduced. Further, since the transfer paths and the transfer roller pairs are not provided, meandering in transferring the stencil sheet can be avoided and mounting position failure of the stencil sheet with regard to the respective printing drums or wrinkle of the stencil sheet by transfer operation can be eliminated. Further, since the transfer paths and the transfer roller pairs are not provided, clogging of the stencil sheet in the transfer path and folding of the front end of the stencil sheet can be eliminated.

Number	Name	Date	Kind
5048416	Iijima	Sep 1991	A
5375516	Hasegawa	Dec 1994	A
6334387	Motoe	Jan 2002	B1

Stencil printing machine

Information

Patent Number

Date Filed

Date Issued

Inventors

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Examiners

Agents

CPC

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US

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Term Extension

Abstract

Description

Claims

Priority Claims (1)

US Referenced Citations (3)

Foreign Referenced Citations (1)

Non-Patent Literature Citations (1)